Method performed by user equipment, and user equipment

ABSTRACT

A method performed by user equipment, including: step A of acquiring time-domain configuration information and/or time-domain indication information; and step B of determining timing-related information according to the time-domain configuration information and/or the time-domain indication information and/or other information.

TECHNICAL FIELD

The present invention relates to a method performed by user equipment, and user equipment.

BACKGROUND

Vehicle-to-Everything (V2X) communication refers to communication between a vehicle and any entity that may affect the vehicle. Typical V2X communication includes V2I (Vehicle-to-Infrastructure), V2N (Vehicle-to-Network), V2V (Vehicle-to-Vehicle), V2P (Vehicle-to-Pedestrian), etc. 3GPP's LTE standards support V2V communication (3GPP V2X phase 1) from Rel-14, and V2X communication (3GPP V2X phase 2) from Rel-15. In the 3GPP standard specifications, the V2V and V2X are both based on D2D (Device to Device) technology, and a corresponding interface between UE and UE is referred to as PC5, also referred to as a “direct” or “side” link (sidelink, or SL for short), to distinguish from uplink (UL for short) and downlink (DL for short).

As 5G NR (see Non-Patent Document 1, hereinafter referred to as 5G for short, or NR, or NR Rel-15, or 5G Rel-15) standardization work progresses, and the 3GPP identifies more advanced V2X service (eV2X service) demands, 3GPP V2X phase 3, i.e., 5G V2X, is on the agenda. In June 2018, a new study item (see Non-Patent Document 2, hereinafter referred as 5G V2X study item for short, or V2X Phase 3 study item) on 3GPP 5G V2X was approved at the 3GPP RAN #80 plenary session. In March 2019, a new work item on 3GPP 5G V2X (see Non-Patent Document 3, hereinafter referred as 5G V2X work item for short) was approved at the 3GPP RAN #83 plenary session. Goals of the 5G V2X work item include:

-   -   design of SL signals, channels, bandwidth parts (BWP), and         resource pools;     -   design of resource allocation mechanisms;     -   design of SL synchronization mechanisms;     -   coexistence of SL operations for LTE and NR;     -   SL physical layer procedures, e.g., a HARQ (hybrid automatic         repeat request) procedure, CSI (channel-state information)         acquisition and power control, etc.;     -   congestion control;     -   layer 2/layer 3 protocols and signaling;     -   control of an LTE SL over an NR Uu interface;     -   gNB scheduling based on UE reporting assistance information; and     -   QoS management.

In 5G V2X, a physical layer of an SL interface supports broadcast, groupcast, and unicast transmissions in in-coverage, out-of-coverage, and partial-coverage scenarios.

5G V2X supports an SL synchronization function. Relevant signals and channels include:

-   -   an SL PSS (sidelink primary synchronization signal), also known         as S-PSS, or PSSS (primary sidelink synchronization signal);     -   an SL SSS (sidelink secondary synchronization signal), also         known as S-SSS or SSSS (secondary sidelink synchronization         signal); and     -   a PSBCH (physical sidelink broadcast channel).

In 5G V2X, a SL PSS, a SL SSS, and a PSBCH are organized into the form of a block in a time-frequency resource grid, called SL SSB (sidelink SS/PBCH block, sidelink synchronization signal/physical broadcast channel block), or S-SSBs. The transmission bandwidth of a SL SSB is within an SL BWP (sidelink bandwidth part) configured for UE. The SL PSS and/or the SL SSS may carry an SL SSID (sidelink synchronization identity, or sidelink synchronization identifier, or sidelink synchronization signal identity, or sidelink synchronization signal identifier), and the PSBCH may carry an SL MIB (sidelink master information block, also referred to as S-MIB or MIB-SL or MIB-SL-V2X).

A synchronization source (sometimes also referred to as a synchronization reference, or as a synchronization reference source) for 5G V2X may include a GNSS (global navigation satellite system), a gNB, an eNB, and NR UE. The priority definition of the synchronization sources is shown in Table 1. UE uses (pre)configuration information to determine whether to use “GNSS-based synchronization” or “gNB/eNB-based synchronization.” Examples of the GNSS include the GPS (Global Positioning System), the GLONASS (Global Navigation Satellite System), the BeiDou (Beidou Navigation Satellite System), the Galileo (Galileo Navigation Satellite System), the QZSS (Quasi-Zenith Satellite System), etc.

TABLE 1 5G V2X synchronization source priority Priority GNSS-based synchronization gNB/eNB-based synchronization P0 GNSS gNB/eNB P1 All UE directly synchronized to GNSS All UE directly synchronized to gNB/eNB P2 All UE indirectly synchronized to GNSS All UE indirectly synchronized to gNB/eNB P3 Any other UE GNSS P4 N/A All UE directly synchronized to GNSS P5 N/A All UE indirectly synchronized to GNSS P6 N/A Any other UE

In the out-of-coverage scenario, and in an RRC_IDLE state, one SL BWP may be (pre)configured on one 5G V2X carrier. In the in-coverage scenario, there is only one active SL BWP on one 5G V2X carrier. One or a plurality of resource pools (which refers to a time-frequency resource set that can be used for SL transmission and/or reception) may be (pre)configured on one SL BWP.

Resource allocation modes for 5G V2X may be categorized as follows:

-   -   Mode 1: A base station schedules SL resources for SL         transmission.     -   Mode 2: UE determines the SL resources for SL transmission         (i.e., the base station does not participate in scheduling of         the SL resources).

Other channels involved in 5G V2X include at least:

-   -   a PSSCH (physical sidelink shared channel);     -   a PSCCH (physical sidelink control channel); and     -   a PSFCH (physical sidelink feedback channel).

In 5G V2X, transmitter UE can schedule, through SCI (sidelink control information) carried by the PSCCH, transmission of data carried by the PSSCH (in the form of transport blocks (TBs)); receiver UE can indicate, through HARQ feedback information carried in the PSFCH, whether a transport block has been correctly received. Depending on factors such as whether unicast or groupcast or broadcast transmission is being scheduled, and whether HARQ feedback is required, the SCI may at least include one or more of the following:

-   -   a layer-1 source identifier (layer-1 source ID), or a physical         layer source identifier (physical layer source ID);     -   a layer-1 destination identifier (layer-1 destination ID), or a         physical layer destination identifier (physical layer source         ID);     -   a HARQ process identifier (HARQ process ID), or a HARQ process         number;     -   a new data indicator (NDI); and     -   a redundancy version (RV).

In 5G V2X, a method for multiplexing a PSCCH and a PSSCH associated therewith at least includes: a part of the PSCCH and a part of the PSSCH associated therewith use resources overlapping in the time domain but not overlapping in the frequency domain, and another part of the PSCCH and/or another part of the PSSCH use resources not overlapping in the time domain.

In 5G V2X, potential issues of the SL design include at least:

-   -   in the case where a GNSS is used as a synchronization reference         source, how to calculate or derive complete timing information         of a sidelink such as a direct frame number (DFN), a direct         subframe number, and a direct slot number.

PRIOR ART DOCUMENTS Non-Patent Documents

-   Non-Patent Document 1: RP-181474, Revised WID on New Radio Access     Technology -   Non-Patent Document 2: RP-181429, New SID: Study on 5G V2X -   Non-Patent Document 3: RP-190766, New WID on 5G V2X with NR sidelink

SUMMARY

In order to address at least part of the aforementioned issues, the present invention provides a method performed by user equipment, and user equipment.

According to the present invention, proposed is a method performed by user equipment, including: step A of acquiring time-domain configuration information and/or time-domain indication information; and step B of determining timing-related information according to the time-domain configuration information and/or the time-domain indication information and/or other information.

The time-domain configuration information and the time-domain indication information may include one or more of a time zero, a reference time, a target time, and a timing offset.

Herein, the time zero, the reference time, the target time, and the timing offset may each correspond to one parameter.

Herein, the parameter(s) may be configured in a semi-static manner or a dynamic manner.

Additionally, the timing-related information may be timing information of a sidelink (SL).

The timing information of the sidelink may include one or more of a hyper direct frame number, a direct frame number, a direct half-frame number, a direct subframe number, and a direct slot number.

Herein, the direct slot number may be the number of a direct slot in a hyper direct frame, or the number thereof in a direct frame, or the number thereof in a direct half-frame, or the number thereof in a direct subframe.

Furthermore, the direct slot number can be calculated using any one of the following formulas (1) to (20):

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ) ·N _(hyperdirectframe) ^(μ))  (1)

n _(directslot) =└T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directsubframe,μ) ·N _(directsubframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ) ·N _(hyperdirectframe) ^(μ))  (2)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ) ·N _(hyperdirectframe) ^(μ))  (3)

n _(directslot) =└T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod N _(directslot) ^(directsubframe,μ) ·N _(directsubframe) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ) ·N _(hyperdirectframe) ^(μ))  (4)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ))  (5)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directsubframe,μ) ·N _(directsubframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ))  (6)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ))  (7)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directsubframe,μ) ·N _(directsubframe) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ))  (8)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directframe,μ) ·N _(directframe) ^(μ))  (9)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directsubframe,μ) ·N _(directsubframe) ^(directframe,μ) ·N _(directframe) ^(μ))   (10)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(μ))   (11)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod N _(directslot) ^(directsubframe,μ) ·N _(directsubframe) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(μ))  (12)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod N _(directslot) ^(directframe,μ)  (13)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directsubframe,μ) ·N _(directsubframe) ^(directframe,μ))  (14)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ))  (15)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod N _(directslot) ^(directsubframe,μ) ·N _(directsubframe) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ))  (16)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod N _(directslot) ^(directhalfframe,μ)  (17)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directsubframe,μ) ·N _(directsubframe) ^(directhalfframe,μ))  (18)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directsubframe,μ)  (19)

n _(directslot)=└((T _(target) −T _(ref)−Δ_(T))−└T _(target) −T _(ref)−Δ_(T)┘)/T _(directslot) ^(μ)┘  (20)

where n_(directslot) is the direct slot number;

-   -   T_(directslot) ^(μ)is the length of each direct slot;     -   T_(target) is the target time;     -   T_(ref) is the reference time;     -   ΔT is the timing offset;     -   μ is a subcarrier spacing configuration corresponding to the         sidelink;     -   N_(directslot) ^(directframe,μ) is the number of direct slots         included in each direct frame;     -   N_(directframe) ^(hyperdirectframe,μ) is the number of direct         frames included in each hyper direct frame;     -   N_(directslot) ^(directsubframe,μ) is the number of direct slots         included in each direct subframe;     -   N_(directsubfmame) ^(directframe,μ) is the number of direct         subframes included in each direct frame;     -   N_(directhalfframe) ^(directframe,μ) is the number of direct         half-frames included in each direct frame;     -   N_(directslot) ^(directhalfframe,μ) is the number of direct         slots included in each direct half-frame;     -   N_(directsubframe) ^(directhalfframe,μ) is the number of direct         subframes included in each direct half-frame;     -   N_(directslot) ^(directsubframe,μ) is the number of direct slots         included in each direct subframe;     -   N_(hyperdirectframe) ^(μ) is the number of hyper direct frames         included in each hyper direct frame numbering period; and     -   N_(directframe) ^(μ) is the number of direct frames included in         each direct frame numbering period.

Furthermore, the direct slot number may be the number of the direct slot in the hyper direct frame numbering period, or the number thereof in the direct frame numbering period.

Additionally, according to the present invention, proposed is user equipment, including: a processor; and a memory storing instructions, wherein the instructions, when run by the processor, perform the above method.

According to the present invention, it is possible to derive a timing-related parameter of an SL such as a hyper direct frame number, a direct frame number, a direct half-frame number, a direct subframe number, and a direct slot number by using one or more of a time zero, a reference time, a target time, and a timing offset, for example, using a current UTC time, so that all user equipment (UE) and base stations and/or other entities operating on the SL can be synchronized in the timing parameter, ensuring correct transmission and reception of the user equipment (UE) and base stations and/or other entities on the SL.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present invention will be more apparent from the following detailed description in combination with the accompanying drawings, in which:

FIG. 1 is a flowchart showing a method performed by user equipment according to Embodiment 1 of the present invention.

FIG. 2 is a diagram showing an example of a frame structure corresponding to a sidelink.

FIG. 3 is a block diagram schematically showing user equipment according to the present invention.

DETAILED DESCRIPTION

The following describes the present invention in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the present invention should not be limited to the specific embodiments described below. In addition, detailed descriptions of well-known technologies not directly related to the present invention are omitted for the sake of brevity, in order to avoid obscuring the understanding of the present invention.

In the following description, a 5G mobile communication system and its later evolved versions are used as exemplary application environments to set forth a plurality of embodiments according to the present invention in detail. However, it is to be noted that the present invention is not limited to the following implementations, but is applicable to many other wireless communication systems, such as a communication system after 5G and a 4G mobile communication system before 5G.

Some terms involved in the present invention are described below. Unless otherwise specified, the terms used in the present invention adopt the definitions herein. The terms given in the present invention may vary in LTE, LTE-Advanced, LTE-Advanced Pro, NR, and subsequent communication systems, but unified terms are used in the present invention, when applied to a specific system, the terms may be replaced with terms used in the corresponding system.

3GPP: 3rd Generation Partnership Project

AS: Access Stratum

BWP: Bandwidth Part

CA: Carrier Aggregation

CCE: Control Channel Element

CORESET: Control Resource Set

CP: Cyclic Prefix

CP-OFDM: Cyclic Prefix Orthogonal Frequency Division Multiplexing

CRB: Common Resource Block

CRC: Cyclic Redundancy Check

CSI: Channel-State Information

CSS: Common Search Space

DC: Dual Connectivity

DCI: Downlink Control Information

DFN: Direct Frame Number

DFT-s-OFDM: Discrete Fourier Transformation Spread Orthogonal Frequency Division Multiplexing

DL: Downlink

DL-SCH: Downlink Shared Channel

DM-RS: Demodulation Reference Signal

eMBB: Enhanced Mobile Broadband, enhanced mobile broadband communication

eNB: E-UTRAN Node B

E-UTRAN: Evolved UMTS Terrestrial Radio Access Network

FDRA: Frequency Domain Resource Assignment

FR1: Frequency Range 1

FR2: Frequency Range 2

GLONASS: Global Navigation Satellite System

gNB: NR Node B

GNSS: Global Navigation Satellite System

GPS: Global Positioning System

HARQ: Hybrid Automatic Repeat Request

IE: Information Element

IP: Internet Protocol

LCID: Logical Channel ID, Logical Channel Identifier

LTE: Long Term Evolution

LTE-A: Long Term Evolution-Advanced

MAC: Medium Access Control

MAC CE: MAC Control Element

MCG: Master Cell Group

MIB: Master Information Block

MIB-SL: Master Information Block-Sidelink

MIB-SL-V2X: Master Information Block-Sidelink-V2X

MIB-V2X: Master Information Block-V2X

mMTC: Massive Machine Type Communication

NAS: Non-Access Stratum

NDI: New Data Indicator

NR: New Radio

NUL: Normal Uplink

OFDM: Orthogonal Frequency Division Multiplexing

PBCH: Physical Broadcast Channel

PDCCH: Physical Downlink Control Channel

PDCP: Packet Data Convergence Protocol.

PDSCH: Physical Downlink Shared Channel

PSBCH: Physical Sidelink Broadcast Channel

PSCCH: Physical Sidelink Control Channel

PSFCH: Physical Sidelink Feedback Channel

PSSCH: Physical Sidelink Shared Channel

PRB: Physical Resource Block

PSS: Primary Synchronization Signal

PSSS: Primary Sidelink Synchronization Signal

PTAG: Primary Timing Advance Group

PUSCH: Physical Uplink Shared Channel

PUCCH: Physical Uplink Control Channel

QCL: Quasi Co-Location

QoS: Quality of Service

QZSS: Quasi-Zenith Satellite System

RAR: Random Access Response

RB: Resource Block

RE: Resource Element

REG: Resource-Element Group

RF: Radio Frequency

RLC: Radio Link Control

RNTI: Radio Network Temporary Identifier

RRC: Radio Resource Control

RV: Redundancy Version

S-BWP: Sidelink Bandwidth Part

S-MIB: Sidelink Master Information Block

S-PSS: Sidelink Primary Synchronization Signal

S-SSB: Sidelink SS/PBCH Block (Sidelink Synchronization Signal/Physical Broadcast Channel Block)

S-SSS: Sidelink Secondary Synchronization Signal

SCG: Secondary Cell Group

SCI: Sidelink Control Information

SCS: Subcarrier Spacing

SDAP: Service Data Adaptation Protocol

SFN: System Frame Number

SIB: System Information Block

SL: Sidelink

SL BWP: Sidelink Bandwidth Part

SL MIB: Sidelink Master Information Block

SL PSS: Sidelink Primary Synchronization Signal

SL SS: Sidelink Synchronization Signal

SL SSID: Sidelink Synchronization Signal Identity (or Sidelink Synchronization Signal Identifier)

SL SSB: Sidelink SS/PBCH Block (Sidelink Synchronization Signal/Physical Broadcast Channel Block)

SL SSS: Sidelink Secondary Synchronization Signal

SLSS: Sidelink Synchronization Signal

SLSS ID: Sidelink Synchronization Signal Identity (or Sidelink Synchronization Signal Identifier)

SLSSID: Sidelink Synchronization Signal Identity (or Sidelink Synchronization Signal Identifier)

SpCell: Special Cell

SRS: Sounding Reference Signal

SSB: SS/PBCH Block (Synchronization Signal/Physical Broadcast Channel Block)

SSS: Secondary Synchronization Signal

SSSS: Secondary Sidelink Synchronization Signal

STAG: Secondary Timing Advance Group

SUL: Supplementary Uplink

TA: Timing Advance

TAG: Timing Advance Group

TB: Transport Block

TCP: Transmission Control Protocol

TDD: Time Division Duplexing

TPC: Transmit Power Control

UE: User Equipment

UL: Uplink

UMTS: Universal Mobile Telecommunications System

URLLC: Ultra-Reliable and Low Latency Communication

USS: UE-specific Search Space

V2I: Vehicle-to-Infrastructure

V2N: Vehicle-to-Network

V2P: Vehicle-to-Pedestrian

V2V: Vehicle-to-Vehicle

V2X: Vehicle-to-Everything

Unless otherwise specified, in all embodiments and implementations of the present invention,

-   -   An SL MIB (Sidelink Master Information Block) may also be         referred to as an S-MIB, or an MIB-SL. Optionally, when used in         a V2X service, the SL MIB refers to an MIB-SL-V2X.     -   A synchronization reference source may also be referred to as a         synchronization reference, or a synchronization source.

Embodiment 1

A method performed by user equipment according to Embodiment 1 of the present invention will be described below with reference to FIG. 1.

FIG. 1 is a flowchart showing a method performed by user equipment according to Embodiment 1 of the present invention.

As shown in FIG. 1, in Embodiment 1 of the present invention, the steps performed by the user equipment (UE) include: step S101 and step S103.

Specifically, in step S101, time-domain configuration information and/or time-domain indication information is acquired, wherein:

the time-domain configuration information and/or the time-domain indication information may include one or more of the following:

-   -   Time zero, wherein:         -   Optionally, the time zero may use UTC (Coordinated Universal             Time, also known as world uniform time, or world standard             time, or international coordinated time), or may use GMT             (Greenwich Mean Time), or may use other time standards             and/or time formats.         -   Optionally, the time zero may be represented by a numerical             value (for example, a real number, or a decimal number, or a             fractional number, or an integer), denoted as T₀. For             example, T₀=0.         -   Optionally, the value of the time zero may be expressed in             milliseconds, or in seconds, or in microseconds, or in             nanoseconds, or in other time units.         -   Optionally, the time zero may be a predefined time. For             example, the time zero may be 00:00:00 on Jan. 1, 1900 in             the Gregorian calendar (in this case, optionally, the time             zero may also be expressed as the midnight between Thursday,             Dec. 31, 1899 and Friday, Jan. 1, 1900).         -   Optionally, the time zero may correspond to a time zero             parameter (e.g., timeZero). The time zero parameter may be             set as a predefined value, or may be configured or             pre-configured in a semi-static manner, or may be indicated             in a dynamic manner, wherein:             -   Optionally, the time zero parameter may be included in                 an RRC message or a PC5 RRC message, for example,                 included in an MIB, or included in an SIB, or included                 in an MIB-SL, or included in an PSBCH payload, or                 included in pre-configuration information, or included                 in default configuration information, or included in                 other RRC messages or PC5 RRC messages.             -   Optionally, the time zero parameter may be included in a                 MAC CE.             -   Optionally, the time zero parameter may be included in                 downlink control information (DCI).             -   Optionally, the time zero parameter may be included in                 sidelink control information (SCI).         -   Optionally, the time zero may not be explicitly defined. For             example, when the elapsed time (e.g., expressed in             milliseconds) that has elapsed from a first time (e.g., a             reference time as mentioned below) to a second time (e.g., a             target time as mentioned below) is being determined, the             elapsed time may be independent of a specific definition of             the time zero.     -   Reference time, wherein:         -   Optionally, the reference time may use UTC, or may use GMT,             or may use other time standards and/or time formats.         -   Optionally, the reference time may be represented by a             numerical value (for example, a real number, or a decimal             number, or a fractional number, or an integer), denoted as             T_(ref).         -   Optionally, the value of the reference time may be expressed             in milliseconds, or in seconds, or in microseconds, or in             nanoseconds, or in other time units.         -   Optionally, the value of the reference time may be equal to             the elapsed time (e.g., expressed in milliseconds) that has             elapsed from the time zero to the reference time.         -   Optionally, the reference time may be a predefined time. For             example, the reference time may be 00:00:00 on Jan. 1, 1900             in the Gregorian calendar (in this case, optionally, the             reference time may also be expressed as the midnight between             Thursday, Dec. 31, 1899 and Friday, Jan. 1, 1900.)         -   Optionally, the reference time and the time zero may be the             same time (e.g., in this case, T_(ref)=0).         -   Optionally, the reference time may correspond to a             reference-time parameter (e.g., refTime). The reference time             parameter may be set to a predefined value, or may be             configured or pre-configured in a semi-static manner, or may             be indicated in a dynamic manner, wherein:             -   Optionally, the reference time parameter may be included                 in an RRC message or a PC5 RRC message, for example,                 included in an MIB, or included in an SIB, or included                 in an MIB-SL, or included in an PSBCH payload, or                 included in pre-configuration information, or included                 in default configuration information, or included in                 other RRC messages or PC5 RRC messages.             -   Optionally, the reference time parameter may be included                 in a MAC CE.             -   Optionally, the reference time parameter may be included                 in downlink control information (DCI).             -   Optionally, the reference time parameter may be included                 in sidelink control information (SCI).     -   Target time, wherein:         -   Optionally, the target time may use UTC, or may use GMT, or             may use other time standards and/or time formats.         -   Optionally, the target time may be represented by a             numerical value (for example, a real number, or a decimal             number, or a fractional number, or an integer), denoted as             T_(target).         -   Optionally, the value of the target time may be expressed in             milliseconds, or in seconds, or in microseconds, or in             nanoseconds, or in other time units.         -   Optionally, the value of the target time may be equal to the             elapsed time (e.g., expressed in milliseconds) that has             elapsed from the time zero to the target time.         -   Optionally, the target time may be a current time. In this             case, optionally, T_(target) may also be denoted as             T_(currect).         -   Optionally, the target time may be a specified time in the             past or in the future.         -   Optionally, the target time may correspond to a target time             parameter (e.g., targetTime). The target time parameter may             be set to a predefined value, or may be configured or             pre-configured in a semi-static manner, or may be indicated             in a dynamic manner, wherein:             -   Optionally, the target time parameter may be included in                 an RRC message or a PC5 RRC message, for example,                 included in an MIB, or included in an SIB, or included                 in an MIB-SL, or included in an PSBCH payload, or                 included in pre-configuration information, or included                 in default configuration information, or included in                 other RRC messages or PC5 RRC messages.             -   Optionally, the target time parameter may be included in                 a MAC CE.             -   Optionally, the target time parameter may be included in                 downlink control information (DCI).             -   Optionally, the target time parameter may be included in                 sidelink control information (SCI).         -   Optionally, the target time may be acquired from a GNSS,             wherein:             -   Optionally, when the UE selects a GNSS as a                 synchronization reference source, the target time is                 acquired from the GNSS.             -   Optionally, the GNSS may be the GPS (Global Positioning                 System), or may be the GLONASS (Global Navigation                 Satellite System), or may be the BeiDou (BeiDou                 Navigation Satellite System), or may be the Galileo                 (Galileo Navigation Satellite System), or may be the                 QZSS (Quasi-Zenith Satellite System), or may be other                 satellite systems, or may be a combination of different                 satellite systems.         -   Optionally, the target time may be acquired from an internal             clock of the UE, or may be acquired from a gNB, or may be             acquired from an eNB, or may be acquired from other UE(s),             or may be acquired from other time sources or clock sources.     -   Timing offset, wherein:         -   Optionally, the timing offset may be represented by a             numerical value (for example, a real number, or a decimal             number, or a fractional number, or an integer), denoted as             Δ_(T).         -   Optionally, the value of the timing offset may be expressed             in milliseconds, or in seconds, or in microseconds, or in             nanoseconds, or in other time units.         -   Optionally, the timing offset may be a predefined value. For             example, Δ_(T)=0.         -   Optionally, the timing offset may correspond to a timing             offset parameter (e.g., offsetDFN). The timing offset             parameter may be set to a predefined value, or may be             configured or pre-configured in a semi-static manner, or may             be indicated in a dynamic manner, wherein:             -   Optionally, the value of the timing offset parameter is                 from a predefined set. For example, the predefined set                 may be {0, 1, . . . , 1000}, where 0 corresponds to 0                 milliseconds, 1 corresponds to 0.001 milliseconds, 2                 corresponds to 0.002 milliseconds, and so on.                 Optionally, there is one corresponding element −x for                 each non-zero element x in the predefined set.             -   Optionally, if the timing offset parameter has been                 configured, then Δ_(T) is equal to a value configured by                 the timing offset parameter; otherwise Δ_(T)=0.             -   Optionally, if the timing offset parameter has been                 indicated, then Δ_(T) is equal to a value indicated by                 the timing offset parameter; otherwise Δ_(T)=0.             -   Optionally, the timing offset parameter may be included                 in an RRC message or a PC5 RRC message, for example,                 included in an MIB, or included in an SIB, or included                 in an MIB-SL, or included in an PSBCH payload, or                 included in pre-configuration information, or included                 in default configuration information, or included in                 other RRC messages or PC5 RRC messages.             -   Optionally, the timing offset parameter may be included                 in a MAC CE.             -   Optionally, the timing offset parameter may be included                 in downlink control information (DCI).             -   Optionally, the timing offset parameter may be included                 in sidelink control information (SCI).

Additionally, in step S103, timing-related information is determined according to the time-domain configuration information and/or the time-domain indication information and/or other information. For example, timing information of a sidelink (SL) is determined.

wherein:

-   -   Optionally, the sidelink is an interface for communication         between UEs. Optionally, the interface may also be referred to         as an PC5 interface. Optionally, the communication between the         UEs may be referred to as sidelink communication or SL         communication (e.g., V2X SL communication). Optionally, the SL         communication occurs between two or more neighboring UEs.         Optionally, the SL communication uses NR technology; optionally,         in this case, the SL communication may also be referred to as NR         SL communication. Optionally, the SL communication does not         traverse any network node (e.g., a gNB, etc.).     -   Optionally, the timing-related information may be used for the         SL communication, or may be used for other purposes.     -   Optionally, a subcarrier spacing configuration (SCS         configuration) corresponding to the sidelink may be μ. For         example, a subcarrier spacing configuration (pre)configured for         an SL carrier corresponding to the sidelink is μ. As another         example, a subcarrier spacing configuration (pre)configured for         an SL BWP corresponding to the sidelink is μ. As another         example, a subcarrier spacing configuration (pre)configured for         an SL SSB (or S-SSB) corresponding to the sidelink is μ. As         another example, a subcarrier spacing configuration         (pre)configured for a resource pool corresponding to the         sidelink is μ, wherein:         -   Optionally, the subcarrier spacing (SCS) corresponding to μ             may be Δf. For example, μ=0 corresponds to Δf=15 kHz. As             another example, μ=1 corresponds to Δf=30 kHz. As another             example, μ=2 corresponds to Δf=60 kHz. As another example,             μ=3 corresponds to Δf=120 kHz. As another example, μ=4             corresponds to Δf=240 kHz. As another example, for any given             ρ, Δf=2^(μ)·15 kHz.     -   Optionally, in a frame structure corresponding to the sidelink,         -   optionally, each hyper direct frame (or referred to as a             direct hyper frame) numbering period may include             N_(hyperd1recframe) ^(μ) hyper direct frames. Optionally,             N_(hyperdirectframe) ^(μ) may be equal to 1024, or may be             equal to other values.         -   Optionally, each hyper direct frame may include             N_(directframe) ^(hyperdirectframe,μ) direct frames.             Optionally, N_(directframe) ^(hyperdirectframe,μ) may be             equal to 1024, or may be equal to other values.         -   Optionally, one or more of the hyper direct frame,             N_(hyperdirectframe) ^(μ), and N_(directframe)             ^(hyperdirectframe,μ) are not defined.         -   Optionally, each direct frame numbering period may include             N_(directframe) ^(μ) direct frames. Optionally,             N_(directframe) ^(μ) may be equal to 1024, or may be equal             to other values.         -   Optionally, each direct frame may include             N_(directhalfframe) ^(directframe,μ) direct half frames.             Optionally, N_(directhalfframe) ^(directframe,μ) may be             equal to 2, or may be equal to other values.         -   Optionally, each direct frame may include N_(directsubframe)             ^(directframe,μ) direct subframes. Optionally,             N_(directsubframe) ^(directframe,μ) may be equal to 10, or             may be equal to other values.         -   Optionally, each direct frame may include N_(directslot)             ^(directframe,μ) direct slots. Optionally, the value of             N_(directslot) ^(directframe,μ) may be related to μ. For             example, if μ=0, then N_(directslot) ^(directframe,μ)=10. As             another example, if μ=1, then N_(directslot)             ^(directframe,μ)=20. As another example, if μ=2, then             N_(directslot) ^(directframe,μ)=40. As another example, if             μ=3, then N_(directslot) ^(directframe,μ)=80. As another             example, if μ=4, then N_(directslot) ^(directframe,μ)=160.             As another example, for any μ, N_(directslot)             ^(directframe,μ)=10·2^(μ).         -   Optionally, each direct half frame may include             N_(directsubframe) ^(directhalfframe,μ) direct subframes.             Optionally, N_(directsubframe) ^(directhalfframe,μ) may be             equal to 5, or may be equal to other values.         -   Optionally, each direct half frame may include             N_(directslot) ^(directhalfframe,μ) direct slots.             Optionally, the value of N_(directslot) ^(directhalfframe,μ)             may be related to μ. For example, if μ=0, then             N_(directslot) ^(directhalfframe,μ)=5. As another example,             if μ=1, then N_(directslot) ^(directhalfframe,μ)=10. As             another example, if μ=2, then N_(directslot)             ^(directhalfframe,μ)=20. As another example, if μ=3, then             N_(directslot) ^(directhalfframe,μ)=40. As another example,             if μ=4, then N_(directslot) ^(directhalfframe,μ)=80. As             another example, for any μ, N_(directslot)             ^(directhalfframe,μ)=5·2^(μ).         -   Optionally, each direct subframe may include N_(directslot)             ^(directsubframe,μ) direct slots. Optionally, the value of             N_(directslot) ^(directsubframe,μ) may be related to μ. For             example, if μ=0, then N_(directslot) ^(directsubframe,μ)=1.             As another example, if μ=1, then N_(directslot)             ^(directsubframe,μ)=2. As another example, if μ=2, then             N_(directslot) ^(directsubframe,μ)=4. As another example, if             μ=3, then N_(directslot) ^(directsubframe,μ)=8. As another             example, if μ=4, then N_(directslot) ^(directsubframe,μ)=16.             As another example, for any μ, N_(directslot)             ^(directsubframe,μ)=2^(μ).         -   Optionally, the length of each direct frame (or referred to             as duration, denoted as T_(directframe) ^(μ)) may be equal             to 10 milliseconds, or may be equal to other values.         -   Optionally, the length of each direct half frame (or             referred to as duration, denoted as T_(directhalfframe)             ^(μ)) may be equal to 5 milliseconds, or may be equal to             other values.         -   Optionally, the length of each direct subframe (or referred             to as duration, denoted as T_(directsubframe) ^(μ)) may be             equal to 1 millisecond, or may be equal to other values.         -   Optionally, the length of each direct slot (or referred to             as duration, denoted as T_(directslot) ^(μ)) may be related             to μ. For example, T_(directslot) ^(μ)=10/N_(directslot)             ^(directsubframe,μ)milliseconds. Optionally, if             N_(directslot) ^(directsubframe,μ)=10·2^(μ), then             T_(directslot) ^(μ)=10/(10·2^(μ))=2⁻¹ milliseconds. As             another example, T_(slot) ^(μ)=5/N_(directslot)             ^(directsubframe,μ) milliseconds. Optionally, if             N_(directslot) ^(directsubframe,μ)=5·2^(μ), then             T_(directslot) ^(μ)=|5/(5·2^(μ))=2^(−μ)milliseconds. As             another example, T_(directslot) ^(μ)=1/N_(directslot)             ^(directsubframe,μ) milliseconds. Optionally, if             N_(directslot) ^(directsubframe,μ)=2^(μ), then             T_(directslot) ^(μ)=1/2^(μ)=2^(−μ) milliseconds.     -   FIG. 2 gives one example of the frame structure, where μ=1         (corresponding to Δf=30 kHz), N_(hyperdirectframe) ^(μ)=1024,         N_(directframe) ^(hyperdirectframe,μ)=1024, N_(directhalfframe)         ^(directframe,μ)=2, N_(directsubframe) ^(directframe,μ)=10,         N_(directsubframe) ^(directhalfframe,μ)=5, N_(directslot)         ^(directframe,μ)=10·2^(μ)=20, N_(directslot)         ^(directhalfframe,μ)=5·2^(μ)=10, N_(directslot)         ^(directsubframe,μ)=2^(μ)=2, T_(directframe) ^(μ)=10         milliseconds, T_(directhalfframe) ^(μ)=5 milliseconds,         T_(directsubframe) ^(μ)=1 milliseconds, T_(directslot)         ^(μ)=2^(=μ)=0.5 milliseconds. Optionally, N_(directframe)         ^(μ)=1024 Optionally, one or more of the hyper direct frame,         N_(hyperdirectframe) ^(μ), and N_(directframe)         ^(hyperdirectframe,μ) are not defined.     -   Optionally, the timing information of the sidelink may include         any one or more of the following:         -   Hyper direct frame number (H-DFN), denoted as n_(hdfn).         -   wherein:             -   Optionally, the hyper direct frame number may be the                 number of the hyper direct frame in a hyper direct frame                 numbering period. Optionally, a value set of the hyper                 direct frame number may be {0, 1, . . . ,                 N_(hyperdirectframe) ^(μ)−1}, or may be other sets.             -   Optionally, the hyper direct frame number may be                 calculated according to any one of the following:

n _(hdfn)=└(T _(target) −T _(ref)−Δ_(T))/(N _(directframe) ^(hyperdirectframe,μ) ·T _(directframe) ^(μ))┘ mod N _(hyperdirectframe) ^(μ)

n _(hdfn)=└(T _(target) −T _(ref)−Δ_(T))/(N _(directframe) ^(μ) ·T _(directframe) ^(μ))┘ mod N _(hyperdirectframe) ^(μ)

-   -   -   -   For example, if N_(directframe)                 ^(hyperdirectframe,μ)=1024, N_(hyperdirectframe)                 ^(μ)=1024, N_(directframe) ^(μ)=1024, T_(directframe)                 ^(μ)=10 milliseconds, then the hyper direct frame number                 may be calculated according to any one of the following:

n _(hdfn)=└(T _(target) −T _(ref)−Δ_(T))/10240┘ mod 1024

n _(hdfn)=└(T _(target) −T _(ref)−Δ_(T))/(1024·10)┘ mod 1024

n _(hdfn)=└0.1·└(T _(target) −T _(ref)−Δ_(T))/1024┘ mod 1024

-   -   -   Direct frame number (DFN), denoted as n_(dfn), wherein:             -   Optionally, the direct frame number may be the number of                 the direct frame in the hyper direct frame numbering                 period. Optionally, a value set of the direct frame                 number may be {0, 1, . . . , N_(directframe)                 ^(hyperdirectframe,μ)·N_(hyperdirectframe) ^(μ)−1}, or                 may be other sets.             -   Optionally, the direct frame number may be the number of                 the direct frame in a hyper direct frame. Optionally, a                 value set of the direct frame number may be (0, 1, . . .                 , N_(directframe) ^(hyperdirectframe,μ), or may be other                 sets.             -   Optionally, the direct frame number may be the number of                 the direct frame in a direct frame numbering period.                 Optionally, a value set of the direct frame number may                 be {0, 1, . . . , N_(directframe) ^(μ)−1}, or may be                 other sets.             -   Optionally, the direct frame number may be calculated                 according to any one of the following:

n _(dfn)=└(T _(target) −T _(ref)−Δ_(T))/T _(directframe) ^(μ)┘ mod(N _(directframe) ^(hyperdirectframe,μ) ·N _(hyperdirectframe) ^(μ))

n _(dfn)=└(T _(target) −T _(ref)−Δ_(T))/T _(directframe) ^(μ)┘ mod N _(directframe) ^(hyperdirectframe,μ)

n _(dfn)=└(T _(target) −T _(ref)−Δ_(T))/T _(directframe) ^(μ)┘ mod N _(directframe) ^(μ)

-   -   -   -   For example, if N_(directframe)                 ^(hyperdirectframe,μ)=1024, N_(hyperdirectframe)                 ^(μ)=1024, N_(directframe) ^(μ)=1024, T_(directframe)                 ^(μ)=₁₀ milliseconds, then the direct frame number may                 be calculated according to any one of the following:

n _(dfn)=└(T _(target) −T _(ref)−Δ_(T))/10┘ mod 1048576

n _(dfn)=└0.1(T _(target) −T _(ref)−Δ_(T))┘ mod 1048576

n _(dfn)=└(T _(target) −T _(ref)−Δ_(T))/10┘ mod 1024

n _(dfn)=└0.1·(T _(target) −T _(ref)−Δ_(T))┘ mod 1024

-   -   Direct half frame number (DHFN), denoted as n_(dhfn), wherein:         -   Optionally, the direct half frame number may be the number             of the direct half frame in the hyper direct frame numbering             period. Optionally, a value set of the direct half frame             number may be {0, 1, . . . , N_(directhalfframe)             ^(directframe,μ)·N_(directframe)             ^(hyperdirectframe,μ)·N_(hyperdirectframe) ^(μ)−1}, or may             be other sets.         -   Optionally, the direct half frame number may be the number             of the direct half frame in a hyper direct frame.             Optionally, the value set of the direct half frame number             may be {0, 1, . . . , N_(directhalfframe)             ^(directframe,μ)·N_(directframe) ^(hyperdirectframe,μ)}, or             may be other sets.         -   Optionally, the direct half frame number may be the number             of the direct half frame in the direct frame numbering             period. Optionally, the value set of the direct half frame             number may be {0, 1, . . . , N_(directhalfframe)             ^(directframe,μ)·N_(directframe) ^(μ)−1}, or may be other             sets.         -   Optionally, the direct half frame number may be the number             of the direct half frame in a direct frame. Optionally, the             value set of the direct half frame number may be {0, 1, . .             . , N_(directhalfframe) ^(directframe,μ)−1}, or may be other             sets.         -   Optionally, the direct half frame number may be calculated             according to any one of the following:

n _(dhfn)=└(T _(target) −T _(ref)−Δ_(T))/T _(directhalfframe) ^(μ)┘ mod(N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ) ·N _(hyperdirectframe) ^(μ))

n _(dhfn)=└(T _(target) −T _(ref)−Δ_(T))/T _(directhalfframe) ^(μ)┘ mod N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ))

n _(dhfn)=└(T _(target) −T _(ref)−Δ_(T))/T _(directhalfframe) ^(μ)┘ mod(N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(μ))

n _(dhfn)=└(T _(target) −T _(ref)−Δ_(T))/T _(directhalfframe) ^(μ)┘ mod N _(directhalfframe) ^(directframe,μ)

-   -   -   -   For example, if N_(directframe)                 ^(hyperdirectframe,μ)=1024, N_(hyperdirectframe)                 ^(μ)=1024, N_(directframe) ^(μ)=1024,                 N_(directhalfframe) ^(directframe,μ)=2,                 T_(directhalfframe) ^(μ)=5 milliseconds, then the direct                 half frame number may be calculated according to any one                 of the following:

n _(dhfn)=└(T _(target) −T _(ref)−Δ_(T))/5┘ mod 2097152

n _(dhfn)=└0.2·(T _(target) −T _(ref)−Δ_(T))┘ mod 2097152

n _(dhfn)=(T _(target) −T _(ref) −ΔT)/5┘ mod 2048

n _(dhfn)=└0.2·(T _(target) −T _(ref)−Δ_(T))┘ mod 2048

n _(dhfn)=└(T _(target) −T _(ref) −ΔT)/5┘ mod 2

n _(dhfn)=└0.2·(T _(target) −T _(ref)−Δ_(T))┘ mod 2

-   -   -   Direct subframe number, denoted as n_(directsubframe).         -   wherein:             -   Optionally, the direct subframe number may be the number                 of the direct subframe in the hyper direct frame                 numbering period. Optionally, a value set of the direct                 subframe number may be {0, 1, . . . , N_(directsubframe)                 ^(directframe,μ)·N_(directframe)                 ^(hyperdirectframe,μ)·N_(hyperdirectframe) ^(μ)−1}, or                 may be {0, 1, . . . , N_(directsubframe)                 ^(directhalfframe,μ)·N_(directhalfframe)                 ^(directframe,μ)·N_(directframe)                 ^(hyperdirectframe,μ)·N_(hyperdirectframe) ^(μ)−1}, or                 may be other sets.             -   Optionally, the direct subframe number may be the number                 of the direct subframe in a hyper direct frame.                 Optionally, the value set of the direct subframe number                 may be {0, 1, . . . , N_(directsubframe)                 ^(directframe,μ)·N_(directframe)                 ^(hyperdirectframe,μ)−1} or may be {0, 1, . . . ,                 N_(directsubframe)                 ^(directhalfframe,μ)·N_(directhalfframe)                 ^(directframe,μ)·N_(directframe)                 ^(hyperdirectframe,μ)−1}, or may be other sets.             -   Optionally, the direct subframe number may be the number                 of the direct subframe in the direct frame numbering                 period. Optionally, the value set of the direct subframe                 number may be {0, 1, . . . , N_(directsubframe)                 ^(directframe,μ)·N_(directframe) ^(μ)−1}, or may be {0,                 1, . . . , N_(directsubframe)                 ^(directhalfframe,μ)·N_(directhalfframe)                 ^(directframe,μ)·N_(directframe) ^(μ)−1}, or may be                 other sets.             -   Optionally, the direct subframe number may be the number                 of the direct subframe in a direct frame. Optionally,                 the value set of the direct subframe number may be {0,                 1, . . . , N_(directsubframe) ^(directframe,μ)−1}, or                 may be {0, 1, . . . , N_(directsubframe)                 ^(directhalfframe,μ)·N_(directhalfframe)                 ^(directframe,μ)−1}, or may be other sets.             -   Optionally, the direct subframe number may be the number                 of the direct subframe in a direct half frame.                 Optionally, the value set of the direct subframe number                 may be {0, 1, . . . , N_(directsubframe)                 ^(directhalfframe,μ)−1}, or may be other sets.             -   Optionally, the direct subframe number may be calculated                 according to any one of the following:

n _(directsubframe)=└(T _(target) −T _(ref)−Δ_(T))/T _(directsubframe) ^(μ)┘ mod(N _(directsubframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ) ·N _(hyperdirectframe) ^(μ))

n _(directsubframe)=└(T _(target) −T _(ref)−Δ_(T))/T _(directsubframe) ^(μ)┘ mod(N _(directsubframe) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ) ·N _(hyperdirectframe) ^(μ))

n _(directsubframe)=└(T _(target) −T _(ref)−Δ_(T))T _(directsubframe) ^(μ)┘ mod(N _(directsubframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ))

n _(directsubframe)=└(T _(target) −T _(ref)−Δ_(T))/T _(directsubframe) ^(μ)┘ mod(N _(directsubframe) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ))

n _(directsubframe)=└(T _(target) −T _(ref)−Δ_(T))/T _(directsubframe) ^(μ)┘ mod(N _(directsubframe) ^(directframe,μ) ·N _(directframe) ^(μ))

n _(directsubframe)=└(T _(target) −T _(ref)−Δ_(T))/T _(directsubframe) ^(μ)┘ mod(N _(directsubframe) ^(directframe,μ) ·N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(μ))

n _(directsubframe)=└(T _(target) −T _(ref)−Δ_(T))/T _(directsubframe) ^(μ)┘ mod N _(directsubframe) ^(directframe,μ)

n _(directsubframe)=└(T _(target) −T _(ref)−Δ_(T))T _(directsubframe) ^(μ)┘ mod(N _(directsubframe) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ))

n _(directsubframe)=└(T _(target) −T _(ref)−Δ_(T))/T _(directsubframe) ^(μ)┘ mod N _(directsubframe) ^(directhalfframe,μ)

-   -   -   -   For example, if N_(directframe)                 ^(hyperdirectframe,μ)=1024, N_(directframe) ^(μ)=1024,                 N_(directhalfframe) ^(directframe,μ)=2,                 N_(directsubframe) ^(directframe,μ)=10,                 N_(directsubframe) ^(directhalfframe,μ)=5,                 T_(directsubframe) ^(μ)=1 millisecond, then the direct                 subframe number may be calculated according to any one                 of the following:

n _(directsubframe) =└T _(target) −T _(ref)−Δ_(T)┘ mod 10485760

n _(directsubframe) =└T _(Target) −T _(ref)−Δ_(T)┘ mod 10240

n _(directsubframe) =└T _(target) −T _(ref)−Δ_(T)┘ mod 10

n _(directsubframe) =└T _(Target) −T _(ref)−Δ_(T)┘ mod 5

-   -   -   Direct slot number, denoted as n_(directslot), wherein:             -   Optionally, the direct slot number may be the number of                 the direct slot in the hyper direct frame numbering                 period. Optionally, a value set of the direct slot                 number may be {0, 1, . . . , N_(directslot)                 ^(directframe,μ)·N_(directframe)                 ^(hyperdirectframe,μ)·N_(hyperdirectframe) ^(μ)−1}, or                 may be {0, 1, . . . , N_(directslot)                 ^(subframe,μ)·N_(directsubframe)                 ^(directframe,μ)·N_(directframe)                 ^(hyperdirectframe,μ)·N_(hyperdirectframe) ^(μ)−1}, or                 may be {0, 1, . . . , N_(directslot)                 ^(directhalfframe,μ)·N_(directhalfframe)                 ^(directframe,μ)·N_(directframe)                 ^(hyperdirectframe,μ)·N_(hyperdirectframe) ^(μ)−1}, or                 may be {0, 1, . . . , N_(directslot)                 ^(directsubframe,μ)·N_(directsubframe)                 ^(directhalfframe,μ)·N_(directhalfframe)                 ^(directframe,μ)·N_(directframe)                 ^(hyperdirectframe,μ)·N_(hyperdirectframe) ^(μ)−1}, or                 may be other sets.             -   Optionally, the direct slot number may be the number of                 the direct slot in a hyper direct frame. Optionally, the                 value set of the direct slot number may be {0, 1, . . .                 , N_(directslot) ^(directframe,μ)·N_(directframe)                 ^(hyperdirectframe,μ)−1}, or may be {0, 1, . . . ,                 N_(directslot) ^(directsubframe,μ)·N_(directsubframe)                 ^(directframe,μ)·N_(directframe)                 ^(hyperdirectframe,μ)−1}, or may be {0, 1, . . . ,                 N_(directslot) ^(directhalfframe,μ)·N_(directhalfframe)                 ^(directframe,μ)·N_(directframe)                 ^(hyperdirectframe,μ)−1}, or may be {0, 1, . . . ,                 N_(directslot) ^(directsubframe,μ)·N_(directsubframe)                 ^(directhalfframe,μ)·N_(directhalfframe)                 ^(directframe,μ)·N_(directframe)                 ^(hyperdirectframe,μ)−1}, or may be other sets.             -   Optionally, the direct slot number may be the number of                 the direct slot in the direct frame numbering period.                 Optionally, the value set of the direct slot number may                 be {0, 1, . . . , N_(directslot)                 ^(directframe,μ)·N_(directframe) ^(μ)−1}, or may be {0,                 1, . . . , N_(directslot)                 ^(directsubframe,μ)·N_(directsubframe)                 ^(directframe,μ)·N_(directframe) ^(μ)−1}, or may be {0,                 1, . . . , N_(directslot)                 ^(directhalfframe,μ)·N_(directhalfframe)                 ^(directframe,μ)·N_(directframe) ^(μ)−1}, or may be {0,                 1, . . . , N_(directslot) ^(directsubframe,μ),                 N_(directsubframe)                 ^(directhalfframe,μ)·N_(directhalfframe)                 ^(directframe,μ)·N_(directframe) ^(μ)−1}, or may be                 other sets.             -   Optionally, the direct slot number may be the number of                 the direct slot in a direct frame. Optionally, the value                 set of the direct slot number may be {0, 1, . . . ,                 N_(directslot) ^(directframe,μ)−1}, or may be {0, 1, . .                 . , N_(directslot)                 ^(directsubframe,μ)·N_(directsubframe)                 ^(directframe,μ)−1}, or may be {0, 1, . . . ,                 N_(directslot) ^(directhalfframe,μ)·N_(directhalfframe)                 ^(directframe,μ)−1}, or may be {0, 1, . . . ,                 N_(directslot) ^(directsubframe,μ)·N_(directsubframe)                 ^(directhalfframe,μ)·N_(directhalfframe)                 ^(directframe,μ)−}, or may be other sets.             -   Optionally, the direct slot number may be the number of                 the direct slot in a direct half frame. Optionally, the                 value set of the direct slot number may be {0, 1, . . .                 , N_(directslot) ^(directsubframe,μ)−1}, or may be {0,                 1, . . . , N_(directslot)                 ^(directsubframe,μ)·N_(directsubframe)                 ^(directhalfframe,μ)−1}, or may be other sets.             -   Optionally, the direct slot number may be the number of                 the direct slot in a direct subframe. Optionally, the                 value set of the direct slot number may be {0, 1, . . .                 , N_(directslot) ^(directsubframe,μ)−1}, or may be other                 sets.             -   Optionally, the direct slot number may be calculated                 according to any one of the following:

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod N _(directslot) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ) ·N _(hyperdirectframe) ^(μ))

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod N _(directslot) ^(directsubframe,μ) N _(directsubframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ) N _(hyperdirectframe) ^(μ))

n _(directslot) =└T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod N _(directslot) ^(directhalfframe,μ) N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ) ·N _(hyperdirectframe) ^(μ))

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directsubframe,μ) ·N _(directsubframe) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ) ·N _(hyperdirectframe) ^(μ))

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ) ·N _(hyperdirectframe) ^(μ))

n _(directslot) =└T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod N _(directslot) ^(directsubframe,μ) ·N _(directsubframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ))

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))┘T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(hyperdirectframe,μ))

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directsubframe,μ) ·N _(directhalfframe) ^(directsubframe,μ) ·N _(directframe) ^(hyperdirectframe,μ))

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directframe,μ) ·N _(directframe) ^(μ))

n _(directslot)└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directsubframe,μ) ·N _(directsubframe) ^(directframe,μ) ·N _(directframe) ^(μ))

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directhalfframe,μ) N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(μ))

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directsubframe,μ) ·N _(directsubframe) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ) ·N _(directframe) ^(μ))

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)mod N _(directslot) ^(directframe,μ)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))T _(directslot) ^(μ)┘ mod N _(directslot) ^(directsubframe,μ) ·N _(directsubframe) ^(directframe,μ))

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod(N _(directslot) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ))

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod N _(directslot) ^(directsubframe,μ) ·N _(directsubframe) ^(directhalfframe,μ) ·N _(directhalfframe) ^(directframe,μ))

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod N _(directslot) ^(directhalfframe,μ)

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod N _(directslot) ^(directsubframe,μ) N _(directsubframe) ^(directhalfframe,μ))

n _(directslot)=└(T _(target) −T _(ref)−Δ_(T))/T _(directslot) ^(μ)┘ mod N _(directslot) ^(directsubframe,μ)

n _(directslot)=(T _(target) −T _(ref)−Δ_(T))−└T _(target) −T _(ref)−Δ_(T) ┘/T _(directslot) ^(μ)┘

-   -   -   For example, if N_(directframe) ^(hyperdirectframe,μ)=1024,             N_(directframe) ^(μ)=1024, N_(hyperdirectframe) ^(μ)=1024,             N_(directslot) ^(directframe,μ)=10·2^(μ), N_(directsubframe)             ^(directframe,μ)=10, N_(directslot)             ^(directsubframe,μ)=2^(μ), N_(directframe)             ^(directframe,μ)=2, N_(directsubframe)             ^(directhalfframe,μ)=5, N_(directslot)             ^(directhalfframe,μ)=5·2^(μ), T_(directslot)             ^(μ)=1/2^(μ)=2^(−μ) milliseconds, then the direct slot             number may be calculated according to any one of the             following:

n _(directslot) =└N _(directslot) ^(directsubframe,μ)·(T _(target) −T _(ref)−Δ_(T))┘ mod(N _(directslot) ^(directframe,μ)·1048576)

n _(slot)=└2^(μ)·(T _(target) −T _(ref)−Δ^(T))┘ mod(2^(μ)·10485760)

n _(directsubframe) =└N _(directslot) ^(directsubframe,μ)·(T _(target) −T _(ref)−Δ_(T))┘ mod(N _(directslot) ^(directframe,μ)·1024)

n _(directslot)=└2^(μ)·(T _(target) −T _(ref)−Δ_(T))┘ mod(2^(μ)·10240)

n _(directslot) =└N _(directslot) ^(directsubframe,μ)(T _(target) −T _(ref)−Δ_(T))┘ mod N _(directslot) ^(directframe,μ)

n _(directslot)=└2^(μ)(T _(target) −T _(ref)−Δ_(T))mod(2^(μ)·10)

n _(directslot) =└N _(directslot) ^(directsubframe,μ)·(T _(target) −T _(ref)−Δ_(T))┘ mod N _(directslot) ^(directhalfframe,μ)

n _(directslot)=└2^(μ)·└(T _(target) −T _(ref)−Δ_(T))┘ mod(2^(μ)·5)

n _(directslot) =└N _(directslot) ^(directsubframe,μ)·(T _(target) −T _(ref)−Δ_(T))┘ mod N _(directslot) ^(directsubframe,μ)

n _(directslot)=└2^(μ)·(T _(target) −T _(ref)−Δ_(T))┘ mod 2^(μ)

n _(directslot) =└N _(directslot) ^(directsubframe,μ)·((T _(Target) −T _(ref)−Δ_(T))−└T _(target) −T _(ref)−Δ_(T)┘)┘

n _(directslot)=└2^(μ)·((T _(Target) −T _(ref)−Δ_(T))−└T _(target) −T _(ref)−Δ_(T)┘)┘

wherein:

-   -   Optionally, the “calculating” may also be referred to as         “deducing”, or may be referred to as “deriving.”     -   Optionally, in the above calculations of the hyper direct frame         number, the direct frame number, the direct half frame number,         the direct subframe number, and the direct slot number, it is         assumed that T_(target), T_(ref), and Δ_(T) are expressed in         milliseconds. Optionally, T_(target), T_(ref), and Δ_(T) may be         expressed in time units other than milliseconds, in which case         (T_(target)−T_(ref)−Δ_(T)) needs to be replaced with         C·(T_(target)−T_(ref)−Δ_(T)) so that         C·(T_(target)−T_(ref)−Δ_(T)) is expressed in milliseconds, where         C is a constant. For example, if T_(target), T_(ref), and Δ_(T)         are expressed in seconds, then C=1000.

Optionally, in Embodiment 1 of the present invention, T_(target)−T_(ref) may be replaced with T_(elapsed), where T_(elapsed) is equal to the elapsed time that has elapsed from the reference time to the target time, wherein:

-   -   Optionally, T_(elapsed) may be a numerical number, for example,         a real number, or a decimal number, or a fractional number, or         an integer.     -   Optionally, T_(elapsed) may be expressed in milliseconds, or in         seconds, or in microseconds, or in nanoseconds, or in other time         units.

Optionally, in Embodiment 1 of the present invention, T_(target)−T_(ref)−Δ_(T) may be replaced with T_(target)−T_(ref)+Δ_(T).

Optionally, in Embodiment 1 of the present invention, the timing offset may not be defined. In this case, T_(target)−T_(ref)−Δ_(T) may be replaced with T_(target)−T_(ref).

Optionally, in Embodiment 1 of the present invention, depending on the value of one or more of N_(hyperdirectframe) ^(μ), N_(directframe) ^(hyperdirectframeμ), N_(directframe) ^(μ), N_(directhalfframe) ^(directframe,μ), N_(directsubframe) ^(directframe,μ), N_(directsubframe) ^(directhalfframe,μ), N_(directslot) ^(directframe,μ), N_(directslot) ^(directhalfframe,μ), N_(directframe) ^(directsubframe,μ), T_(directhalfframe) ^(μ), T_(directsubframe) ^(μ), and T_(directslot) ^(μ), the formula for calculating one or more of n_(hdfn), n_(dfn), n_(dhfn), n_(directsubframe), and n_(directslot) may be simplified or rewritten accordingly. For example, if T_(directsubframe) ^(μ)=1 millisecond, then 1/T_(directslot) ^(μ) is equal to the number of direct slots in one direct subframe (i.e., N_(directslot) ^(directsubframe,μ)); therefore, (T_(target)−T_(ref)−Δ_(T))/T_(directslot) may be replaced with N_(directslot) ^(directsubframe,μ)·(T_(target)−T_(ref)−Δ_(T)).

Optionally, in Embodiment 1 of the present invention, the hyper direct frame may be referred to as a different name, for example, a hyper system frame, a hyper radio frame, or a hyper sidelink (SL) frame, or the like.

Optionally, in Embodiment 1 of the present invention, the hyper direct frame number may be referred to as a different name, for example, a hyper system frame number, a hyper radio frame number, or a hyper sidelink frame number, or the like.

Optionally, in Embodiment 1 of the present invention, the direct frame may be referred to as a different name, for example, a system frame, a radio frame, a sidelink frame, or the like.

Optionally, in Embodiment 1 of the present invention, the direct frame number may be referred to as a different name, for example, a system frame number, a radio frame number, or a sidelink frame number, or the like.

Optionally, in Embodiment 1 of the present invention, the direct half frame may be referred to as a different name, for example, a half direct frame, or a half system frame, or a half radio frame, or a half frame, or a system half frame, or a radio half frame, or a sidelink half frame, or the like.

Optionally, in Embodiment 1 of the present invention, the direct half frame number may be referred to as a different name, for example, a half direct frame number, or a half system frame number, or a half radio frame number, or a half frame number, or a system half frame number, or a radio half frame number, or a sidelink half frame number, or the like.

Optionally, in Embodiment 1 of the present invention, the direct subframe may be referred to as a different name, for example, a subframe, or a system subframe, or a radio subframe, or a sidelink subframe, or the like.

Optionally, in Embodiment 1 of the present invention, the direct subframe number may be referred to as a different name, for example, a subframe number, or a system subframe number, or a radio subframe number, or a sidelink subframe number, or the like.

Optionally, in Embodiment 1 of the present invention, the direct slot may be referred to as a different name, for example, a slot, a system slot, or a radio slot, or a sidelink slot, or the like.

Optionally, in Embodiment 1 of the present invention, the direct slot number may be referred to as a different name, for example, a slot number, or a system slot number, or a radio slot number, or a sidelink slot number, or the like.

Optionally, in Embodiment 1 of the present invention, the UE may be replaced with a base station (for example, an eNB, or a gNB, or other types of base stations), or any other entity capable of operating on a sidelink.

Optionally, in Embodiment 1 of the present invention, when the UE selects a GNSS as the synchronization reference source, step S101 is performed.

Optionally, in Embodiment 1 of the present invention, when the UE selects the GNSS as the synchronization reference source, step S103 is performed.

Optionally, in Embodiment 1 of the present invention, when the UE selects the GNSS as the synchronization reference source, step S101 and step S103 are performed.

In this way, Embodiment 1 of the present invention derives a timing-related parameter of a sidelink such as a hyper direct frame number, a direct frame number, a direct half frame number, a direct subframe number, and a direct slot number by using a current UTC time, so that all user equipment (UE) and base stations and/or other entities operating on the sidelink can be synchronized in the timing parameter, ensuring correct transmission and reception of the user equipment (UE) and base stations and/or other entities on the sidelink.

VARIATION EMBODIMENT

Hereinafter, FIG. 3 is used to illustrate user equipment that can perform the method performed by user equipment described in detail above in the present invention as a variant embodiment.

FIG. 3 is a block diagram showing the user equipment (UE) involved in the present invention.

As shown in FIG. 3, the user equipment 60 includes a processor 601 and a memory 602. The processor 601 may, for example, include a microprocessor, a microcontroller, an embedded processor, or the like. The memory 602 may include, for example, a volatile memory (for example, a random access memory (RAM)), a hard disk drive (HDD), a non-volatile memory (for example, a flash memory), or other memories. Program instructions are stored on the memory 602. The instructions, when run by the processor 601, can perform the foregoing method performed by user equipment as described in detail in the present invention.

The methods and related equipment according to the present invention have been described above in combination with preferred embodiments. It should be understood by those skilled in the art that the methods shown above are only exemplary, and the above embodiments can be combined with one another as long as no contradiction arises. The methods of the present invention are not limited to the steps or sequences illustrated above. The network node and user equipment illustrated above may include more modules. For example, the network node and user equipment may further include modules that can be developed or will be developed in the future to be applied to a base station, an MME, or UE, and the like. Various identifiers shown above are only exemplary, and are not meant for limiting the present invention. The present invention is not limited to specific information elements serving as examples of these identifiers. A person skilled in the art could make various alterations and modifications according to the teachings of the illustrated embodiments.

It should be understood that the above-described embodiments of the present invention may be implemented by software, hardware, or a combination of software and hardware. For example, various components inside the base station and the user equipment in the above embodiments may be implemented through various devices, which include, but are not limited to, analog circuit devices, digital circuit devices, digital signal processing (DSP) circuits, programmable processors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), programmable logic devices (CPLDs), and the like.

In this application, the term “base station” may refer to a mobile communication data and control switching center having specific transmission power and a specific coverage area and including functions such as resource allocation and scheduling, data reception and transmission, and the like. “User equipment” may refer to a user mobile terminal, for example, including terminal devices that can communicate with a base station or a micro base station wirelessly, such as a mobile phone, a laptop computer, and the like.

In addition, the embodiments of the present invention disclosed herein may be implemented on a computer program product. More specifically, the computer program product is a product provided with a computer-readable medium having computer program logic encoded thereon. When executed on a computing device, the computer program logic provides related operations to implement the above technical solutions of the present invention. When executed on at least one processor of a computing system, the computer program logic causes the processor to perform the operations (methods) described in the embodiments of the present invention. Such setting of the present invention is typically provided as software, codes and/or other data structures provided or encoded on the computer readable medium, e.g., an optical medium (e.g., compact disc read-only memory (CD-ROM)), a flexible disk or a hard disk and the like, or other media such as firmware or micro codes on one or more read-only memory (ROM) or random access memory (RAM) or programmable read-only memory (PROM) chips, or a downloadable software image, a shared database and the like in one or more modules. Software or firmware or such configuration may be installed on a computing device such that one or more processors in the computing device perform the technical solutions described in the embodiments of the present invention.

In addition, each functional module or each feature of the base station device and the terminal device used in each of the above embodiments may be implemented or executed by a circuit, which is usually one or more integrated circuits. Circuits designed to execute various functions described in this description may include general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs) or general-purpose integrated circuits, field programmable gate arrays (FPGAs) or other programmable logic devices, discrete gates or transistor logic, or discrete hardware components, or any combination of the above. The general purpose processor may be a microprocessor, or the processor may be an existing processor, a controller, a microcontroller, or a state machine. The aforementioned general purpose processor or each circuit may be configured by a digital circuit or may be configured by a logic circuit. Furthermore, when advanced technology capable of replacing current integrated circuits emerges due to advances in semiconductor technology, the present invention can also use integrated circuits obtained using this advanced technology.

While the present invention has been illustrated in combination with the preferred embodiments of the present invention, it will be understood by those skilled in the art that various modifications, substitutions, and alterations may be made to the present invention without departing from the spirit and scope of the present invention. Therefore, the present invention should not be limited by the above-described embodiments, but should be defined by the appended claims and their equivalents. 

1-10. (canceled)
 11. User equipment (UE) comprising: selection circuitry configured to select a Global Navigation Satellite System (GNSS) as a synchronization reference source; calculation circuity configured to derive a slot number n_(slot) within a frame; and communication circuitry configured to perform NR sidelink communication with use of the slot number n_(slot), wherein the slot number n_(slot) is derived according to the following formula: n _(slot)=└(T _(current) −T _(ref)−Δ_(T))·2^(μ)┘ mod(10·2^(μ)), wherein the parameter T_(current) is a current UTC time obtained from the GNSS, the parameter T_(current) is expressed in milliseconds, the parameter T_(ref) is a reference UTC time 00:00:00 on Gregorian calendar date 1 January, 1900, the parameter T_(ref) is expressed in milliseconds, the parameter Δ_(T) corresponds to a Radio Resource Control (RRC) parameter if the RRC parameter is configured, the parameter Δ_(T) is equal to zero if the RRC parameter is not configured, the parameter Δ_(T) is expressed in milliseconds, the parameter μ is a Subcarrier Spacing (SCS) configuration for the NR sidelink communication, and the parameter μ is equal to one of values 0, 1, 2, and 3 that correspond to SCS of 15 kHz, 30 kHz, 60 kHz and 120 kHz, respectively.
 12. A method performed by User equipment (UE) comprising: selecting a Global Navigation Satellite System (GNSS) as a synchronization reference source; deriving a slot number n_(slot) within a frame; and performing NR sidelink communication with use of the slot number n_(slot), wherein the slot number n_(slot) is derived according to the following formula: n _(slot)=└(T _(current) −T _(ref)−Δ_(T))−2^(μ)┘ mod(10·2^(μ)), wherein the parameter T_(current) is a current UTC time obtained from the GNSS, the parameter T_(current) is expressed in milliseconds, the parameter T_(ref) is a reference UTC time 00:00:00 on Gregorian calendar date 1 Jan. 1900, the parameter T_(ref) is expressed in milliseconds, the parameter Δ_(T) corresponds to a Radio Resource Control (RRC) parameter if the RRC parameter is configured, the parameter Δ_(T) is equal to zero if the RRC parameter is not configured, the parameter Δ_(T) is expressed in milliseconds, the parameter μ is a Subcarrier Spacing (SCS) configuration for the NR sidelink communication, and the parameter μ is equal to one of values 0, 1, 2, and 3 that correspond to SCS of 15 kHz, 30 kHz, 60 kHz and 120 kHz, respectively. 